MonoBehaviour that is accessed globally during scene is loaded.

SceneSingletonMonoBehaviour.cs

using UnityEngine;
using UnityEngine.SceneManagement;

/// <summary>
/// 寿命がSceneのSingletonMonobehaviour
/// </summary>
/// <typeparam name="T"></typeparam>
public abstract class SceneSingletonMonoBeheviour<T> : MonoBehaviour
    where T : SceneSingletonMonoBeheviour<T>{

    /// <summary>
    /// インスタンスを取得する
    /// </summary>
    public static T Instance { get; set; }

    private string SceneName;

    protected void Awake() {
        if (Instance == null) {
            Instance = this as T;

            SceneName = gameObject.scene.name;
            SceneManager.sceneUnloaded += SceneManager_sceneUnloaded;
        }
        else {
            Destroy(gameObject);
        }
    }

    private void SceneManager_sceneUnloaded(Scene scene) {
        if (scene.name != SceneName) return;

        SceneManager.sceneUnloaded -= SceneManager_sceneUnloaded;
        Instance = null;

        Debug.Log("UnLoad SceneSingleton : " + typeof(T).Name);
    }
}